This manual electric wheelchair is a crossbreed of the conventional manual wheelchair and the electric wheelchair, and is designed to mitigate the physical work of a rider through the following procedure: detecting a man power imparted intermittently to a pair of right and left drive wheels by a man power detect means; transmitting a detection signal to a control means through a signal transmit means; causing a drive motor, which is controlled by the control means, to create a supplemental force of a magnitude corresponding to the man power; and transmitting this supplemental force to the right and left drive wheels through a drive force transmit means.
However, with the conventional manual electric wheelchairs, the design adopted for the arrangement of the man power detect means, the signal transmit means, the control means; the drive motor and the drive force transmit means, which constitute a supplemental drive force system, was not the kind wherein these elements are assembled at one place compactly, so that the wires used were numerous and lengthy and the manufacture and assemble work was not easy and the cost was high.
Also, with the conventional manual electric wheelchairs, such construction was not adopted whereby the supplemental drive force system is provided for each drive wheel independently from the chair body, so that it was not easy to detach the drive wheels from the chair body, and hence lacked portability and easiness of storing.
It is therefore an object of the invention to provide a manual electric wheelchair, with which a cost reduction can be achieved through simplification of manufacture and assemble work on account of reduction in number and lengths of the wires resulting from realization of compact and rational arrangement of the supplemental drive force system, and with which wheelchair it becomes highly portable and storable on account of easy detachability of the drive wheels from the chair body.
Incidentally, in the conventional manual electric wheelchairs, since the supplemental drive force system consisted of two symmetrically arranged units each one provided radially outside the periphery of each drive wheel, the bulk of the wheelchair was so large that it was not only difficult to handle it but also troublesome to fold it up when not in use.
It is therefore another object of the invention to provide a manual electric wheelchair, which can be made more compact through effectual utilization of its unoccupied room and which can be made more storable while the effect of mass production is increased.
Now, conventionally, the man power detect means adopted was such as follows: handrims were supported in a manner such that they were freely rotatable relative to the drive wheels, and an elastic means such as a spring is connected between a handrim and a drive wheel, and a relative rotation amount of the handrim, which increases proportionately to the man power imparted to the handrim, is detected with a potentiometer or the like to thereby detect the man power.
However, with the conventional manual electric wheelchairs which adopted the man power detect means as described above, since the handrims were supported freely rotatably by a wheel axle of a small-diameter, so that the rigidity with which the handrim is supported is low and thus it was possible that a rider fails to properly perform the lift-up action (an action performed by a rider to lift his/her body making use of the handrims as the support when mounting and dismounting).
Therefore, it is still another object of the invention to provide a manual electric wheelchair, wherein the handrims are supported by drive wheel hubs which can be machined with high precision and have high rigidity, so that the handrims can be supported with higher rigidity and it is also possible for the handrims to rotate smoothly and for the rider to perform the lift-up action by means of the handrims.
Also, when the offset amount in the direction of the axle (widthwise direction of the wheelchair) between an operation portion of the handrims (the portion by which the rider holds the handrims) and a rotation support portion thereof is large, that moment which works upon the handrims in the lateral direction (the moment which works in such a direction as to bend the handrims sideways with respect to the rotation support portion) becomes large with a result that the sideways play of the handrims increases so that the operability is impaired and the durability of the bearing provided in the rotation support portion is lowered.
Therefore, it is still another object of the invention to provide a manual electric wheelchair, with which the operability of the handrims can be improved through reduction of the sideways play of the handrims, and in which the durability of the bearing of the rotation support portion of the handrims can be improved.
Incidentally, it is necessary to maintain with stability the precision of the man power detect means, which consists of springs, potentiometer, etc., for example, so that this means is required to be highly waterproof and dustproof.
Therefore, it is a further object of the invention to provide a manual electric wheelchair, with which it is possible to maintain the detection precision of the man power detect means at high level stably.
The conventional manual electric wheelchairs still had another problem: since the construction was such that the drive wheels were not easily attached to or detached from the chair body, the wheelchairs were poor in portability and storability.
It is therefore a further object of the invention to provide a manual electric wheelchair, with which it is possible to detach and attach the drive wheels in a one-click manner so easily that the portability and storability are significantly improved.
Now, a battery is indispensable as the electric power source to a manual electric wheelchair, and electricity is supplied from the battery to the drive motor and the control means; then, if a main switch for connecting and disconnecting the battery is integrally incorporated in a drive wheel and the main switch is made detachable from the chair body together with the drive wheel in which it is incorporated, the electric wire connecting the main switch to the battery can be made shorter and more manageable, and at the same time, the drive wheels are easily detached from and attached to the chair body.
Therefore, it is also an object of the invention to provide a manual electric wheelchair, with which it is possible to simplify the overall construction and ease the operation for detaching the drive wheels from and attaching the same to the chair body through dwarfing of the electric wires and wire accessories.